FORT WORTH (CBS 11 NEWS) – The FAA has ordered new inspections on older model Boeing 737’s in order to detect tiny cracks that could lead to tears in the fuselage.

The order comes after two highly publicized incidents involving two Southwest Airlines 737’s.

In July, 2009, a football-sized hole opened up in the rear roof of the aircraft during a flight from Nashville to Baltimore.

The pilot made an emergency landing. No one was injured.

The hole opened up due to unanticipated metal fatigue.

While the FAA ordered more inspections after the 2009 incident, the agency now says additional action is needed to assure safety.

In a statement, the FAA says, “This superseding airworthiness directive requires further inspections in more areas, installing additional reinforcements; performing repetitive inspections for loose fasteners and replacement if necessary; and installing a permanent repair. The (directive) also changes initial compliance times and repetitive intervals.”

The order is for all U.S. airlines that operate the Boeing 737-300, 400, 500 models in question.

Southwest Airlines says 78 of its 737-300 and 500 models are part of the directive.

A spokeswoman with the Dallas-based airline, Brandy King says “Safety is paramount at Southwest Airlines. We are prepared to comply and don not anticipate impact to Southwest flight schedules or operations. We remain completely confident in the airworthiness of our fleet.